Behold the Bullet List

A new way of looking at the cause and effect diagram

When using a cause and
effect diagram to find root causes, beware of clutter. Using a list instead of
a diagram makes the cause and effect tool easier to use and allows more
flexibility.

But whether you use the traditional diagram
or a bullet list, put the same powerful concept to work.

First, find the root causes—then
begin problem solving. If you solve a problem before you know what caused it,
it is likely you have not really solved the problem. And, chances are, it will
return.

A
powerful tool for finding root causes is the cause and effect diagram, which Karou Ishikawa invented in the 1960s (see Online Figure 1).
The cause and effect diagram is sometimes called an Ishikawa or fishbone
diagram.

Without this tool’s discipline, we might
stop before we find the root cause. By using the cause and effect tool, we
continue to search all the major categories of causes, increasing the
likelihood of finding the real root cause.

Starting out

To create a cause and effect diagram,
start with an arrow pointing to a box. Write the problem in the box. Draw
arrows to the line from the major categories of causes. In this example, we
used people, materials, methods, equipment, measurements and environment (see
Online Figure 2).

Study
the process to determine causes from each category. For equipment, lubrication,
speed and setup are possible causes. For people, training, fatigue, skills and
motivation might be important. For methods, possibilities include definition and sequence.

Measurements might include instruments and
calibration. For environment, light, temperature, humidity and vibration could
be appropriate.

During the initial search, use the
brainstorming rule—withhold judgment—to make sure you don’t miss a
cause that might prove to be the problem’s root cause. Evaluations should be
done later.

As you develop diagrams, it becomes more
difficult to record more causes. The clutter might result in good ideas being
overlooked or not recorded at all.

A changeup

Recently, in one of Conbraco’s
Calibration College classes, I learned a better way to perform cause and effect searches. This method is easier to create and makes
recording causes more flexible.

Conbraco employee
Jenny Stavrakas knew about cause and effect diagrams
but was bothered by their clutter. So, she developed a format to reduce clutter
while keeping the tool’s simplicity and power.

Stavrakas’ technique is
to create lists on a whiteboard, flip chart, sheets of
paper taped on walls or on a computer. She nicknamed them cause and effect
bullet lists. These lists work well when you can project them on a screen so
everyone developing them can see causes as they are recorded.

Enlisted

To work with your team in developing a
list, first record the problem. Start with one category, and list all the
causes that might be creating the problem. Get inputs from appropriate people,
such as operators, technical experts and maintenance workers. Continue through
the other categories. Stopping too soon might result in missing the real root
cause.

Then,
identify the most likely root causes, and test for a cause and effect
relationship (consider using a scatter diagram). Correct the causes creating the
problem, and then change the process, confirm the new results and establish
controls to make sure the new process is used.

For example, let’s use some of the content
from the fishbone diagram example in Online Figure 2:

Try a cause and effect bullet list to
experience its simplicity and flexibility. Whether using a diagram or a list,
finding the root causes before beginning problem solving is key.

Jack Dearing is the manager
of Conbraco Calibration Services in Pageland, SC. He
earned a bachelor’s degree in political science from Lafayette College in
Easton, PA. Dearing is a senior member of ASQ and an ASQ-certified calibration
technician.

Jenny Stavrakas is the customer service representative at Conbraco Calibration Services. She actively participates in
the laboratory’s weekly Calibration College program. Stavrakas
is an ASQ-certified calibration technician.